Original article • Articolo originale
Reading the mind: a comparative study of out- and inpatients
Lettura della mente: uno studio comparato su pazienti dimessi e pazienti ospedalizzati
A. Geraci, M.S. Signorelli, E. Aguglia
Psychiatry Unit, University Hospital of Catania
Summary
Objectives
Theory of Mind (ToM) is the ability to make inferences on
the mental states of others. This study investigates the stateindependence and the state dependence of theory of mind
(ToM) impairments in schizophrenia.
Methods
We compared the performance of healthy controls, discharged
and hospitalized patients with schizophrenia on three wellknown ToM tasks, requiring mental state recognition from
eyes, inferences about the mental states of others and secondorder false belief attribution. Twenty-nine patients (males and
females) with schizophrenia were recruited (age range, 18-50
years) in the Psychiatric Unit of the University Hospital in Catania (Italy). Patients symptomatology was assessed with the
positive and negative symptoms of schizophrenia (PANSS)
scale. All subjects completed the Raven progressive matrices,
and from this score a relative measure of general intellectual
functioning was indirectly calculated. An Italian adaptation
of Baron-Cohen’s Eyes Test was used. Participants were presented with 10 faux pas stories. 11 Two second-order belief
tasks (birthday puppy and chocolate bar 12) were used.
Results
All groups of patients performed significantly worse than controls on the three ToM tests.
Introduction
Theory of Mind (ToM) is the ability to make inferences on
the mental states of others. ToM deficits in schizophrenia
have been investigated by a large number of studies since
Frith 1 proposed a model supporting a relationship between mentalizing (ToM) impairment and specific symptoms of schizophrenia. Frith’s concept of ToM deficit in
schizophrenia suggested a state-related impairment, and
proposed that the psychotic symptoms in schizophrenia
might be explained by mentalizing impairment.
A theoretical model by Harde-Bayle 2 suggested an association of ToM impairment with another symptom dimension of schizophrenia (disorganized thought), and
On the Eyes Test, control subjects performed better than the
outpatients (t (27) = 4.4, p < .001), inpatients with positive
schizophrenia (t (31) = 6.3, p < .001) and inpatients with
negative schizophrenia (t (26) = 6.2, p < .001). On the faux
pas test, control subjects also performed better than outpatients (t (27) = 13.5, p < .001), in patients with positive
schizophrenia (t (30) = 11.4, p < .001) and in patients with
negative schizophrenia (t (26) = 13.5, p < .001).
In almost all cases, the results were maintained after controlling for the mediating effect of IQ. ToM scores did not differ
significantly between groups. The results revealed the presence of a specific cognitive impairment in representing and
reasoning about mental states. This psychological-reasoning
system is composed, to a large extent, of unconscious processes (modularity theory), and can be fractionated into two
main subsystems, one dedicated, in most proposals, to reasoning about goals and perception (actional or teleological
understanding) and the other to belief-desire reasoning.
Conclusions
These results support the state independence of ToM impairment in schizophrenia. However, the results provide several
recommendations for future studies. One important issue is to
further test the role of ToM impairment in activity of daily life
in patients with schizophrenia.
Key words
Theory of Mind • Schizophrenia • State-independent trait • IQ
also considered the ToM deficit as a state characteristic
of schizophrenia.
A meta-analysis has shown that ToM deficits in “remitted” patients were less pronounced than in non-remitted
patients, and only in the remission phase is there an important role of IQ in ToM tasks 3. These results suggested
that there is trait-related mentalizing impairment in schizophrenia.
Other studies have supported the idea that patients with
schizophrenia have a state-independent impairment in
ToM. This deficit does not seem to be a consequence of
the severity of symptomatology, or to be caused by other
cognitive impairments 4 5.
However, some studies comparing the performance of
Correspondence
Alessandra Geraci, UO Psichiatria, AOU Policlinico “Vittorio Emanuele”, via S. Sofia 78, Catania, Italy • E-mail: [email protected]
Journal of Psychopathology 2012;18:247-250
247
A. Geraci et al.
discharged and hospitalized patients have reported different results, with contrasting conclusions 6-9.
While there is no doubt that schizophrenia patients perform poorly on ToM tasks, there are important issues that
have not been adequately considered in previous studies.
The main issues relate to: (i) heterogeneity of ToM tasks
and their different cognitive demands (social perception,
inferential reasoning, second order false belief attributions); (ii) the influence of clinical and demographic characteristics on ToM performance.
The aim of the current study was to investigate the stateindependent and state-dependent components of ToM
impairment in patients with schizophrenia. Tests for social perception (reading the mind in the eyes test 10) and
inferential reasoning (Faux-pas test 11; second-order false
belief tasks 12) were employed.
We measured state-independent impairments by comparing healthy controls with outpatients. State-dependent
impairments were measured by comparing outpatients
and inpatients. The potential mediating effect of IQ on
performance was also assessed 13. We expected the same
performance in both groups of patients, relating to the
state independence of ToM impairment in schizophrenia.
Methods
Participants
Twenty-nine patients (males and females) with schizophrenia were recruited (age range, 18-50 years) in the
Psychiatric Unit of the University Hospital in Catania (Italy). Diagnosis was confirmed by psychiatrists using the
structured clinical interview for DSM-IV Axis I Disorders
(SCID-I). Patients with neurological problems, mental retardation, diagnosis of Axis II DSM-IV TR or other comorbid psychiatric disorders were excluded. All patients
were treated with second-generation antipsychotic drugs.
Patients were divided in three groups: hospitalized patients with positive schizophrenia, hospitalized patients
with negative schizophrenia and outpatients. These latter lived in their homes and were invited to the hospital
for the purposes of the study 14. Twenty aged-matched
healthy volunteers (HC) served as controls (Table I). One
hospitalized patient with positive schizophrenia did not
complete the Faux pas task and was excluded from the
analysis of this task.
Stimuli and Procedure
Patients symptomatology was assessed with the positive and negative symptoms of schizophrenia (PANSS 15)
scale. All subjects completed the Raven progressive matrices, and from this score a relative measure of general
intellectual functioning was indirectly calculated.
ToM – perception: eyes test. An Italian adaptation of Baron-Cohen’s Eyes Test was used 16. Participants were presented 36 black and white photographs showing the ocular regions of male and female adults. On each trial, first
a photograph was presented and participants were asked
a control question about the gender of the person in the
photo. Then, four adjectives describing complex emotions
or other mental states (e.g. dispirited, bored, embarrassed,
flirting) were shown below the picture and participants
were asked to choose the adjective that best described
the emotion represented in the photographs. Participants
were asked to read all four adjectives before making their
choice, and if they felt that more than one adjective was
applicable, to ‘choose just one that was considered to be
most suitable’. The Experimenter asked: ‘Which adjective
best describes what this person is feeling or thinking?’.
Following the procedure used by Baron-Cohen et al. 10,
participants were encouraged to consult a glossary of all
words used in the task whenever they felt they were not
sure about their meaning. To minimize the negative effects of impulsive tendencies, patients were asked to look
at the stimuli for 30 s before responding. The maximum
score on test and control questions was 36.
ToM – reasoning: the faux-pas test. Participants were presented with 10 faux pas stories 11. A first question assessed
whether the patient detected the faux pas: ‘In the story,
did someone say something that they shouldn’t have
said?’. If subject answered ‘yes’ to the first question, then
he/she was asked five other test questions. Subjects who
answered ‘no’ to the first question were not asked the
remaining test questions and received score a 0 for that
item (maximum score = 60).
Table I.
Clinical features of study participants. Caratteristiche cliniche dei partecipanti allo studio.
State
N
Symptoms
(PANSS)
Age
Education
IQ
Eyes Test
Faux-pas
Test
Second-order
FB
Inpatient
13
Positive
30.6 (10.4)
10.1 (3.07)
74 (15.6)
17.5 (5.01)
18.2 (14.0)
1.8 (1.6)
Inpatient
8
Negative
38.5 (9.3)
8.5 (2.8)
61.3 (18.6)
18.1 (2.1)
16.8 (10.8)
2.2 (1.5)
Outpatient
9
Negative
41.1 (4.5)
9.1 (1.8)
89.7 (11.8)
20.1 (4.4)
22.8 (6.7)
1.3 (1.5)
Control
20
–
36.0 (9.2)
11.4 (2.2)
94.9 (5.3)
27.7 (4.1)
56.2 (4.3)
3.9 (0.2)
248
Reading the mind: a comparative study of out- and inpatients
Second-order false belief task. Two second-order belief
tasks (birthday puppy and chocolate bar 12) were used.
Each task included two control questions and a first-order false belief question. Participants were corrected if
they failed on these questions. At the end of the task, two
test questions were asked (second-order ignorance and
second-order belief questions). Participants received one
point for each correct answer (maximum score = 4).
Results
The clinical features and ToM scores of participants are
reported in table 1. Outpatients and hospitalized patients
with negative schizophrenia differed significantly in the
IQ score (t (15) = 3.78, p = .002). Outpatients and hospitalized patients with positive schizophrenia also differed
significantly in both the IQ score (t (20) = 2.13, p = .046)
and age (t (20) = 2.96, p = .008), just as control subjects differed significantly in the IQ score vs inpatients
with positive schizophrenia (t (31) = 4.93, p < .001) and
vs patients with negative schizophrenia (t (26) = 7.44,
p < .001). Controls subjects differed significantly in
level of education vs outpatients (t (27) = 2.74, p = .01)
and patients with negative schizophrenia (t (26) = 2.93,
p = .007).
The scores of the three groups of patients were significantly lower than those of control subjects for all ToM
tests. The performance of the three groups of patients
did not differ significantly on any of the ToM tests. There
was no significant correlation between the IQ score and
ToM for any of the patient groups. On the Eyes Test,
control subjects performed better than the outpatients
(t (27) = 4.4, p < .001), inpatients with positive schizophrenia (t (31) = 6.3, p < .001) and inpatients with
negative schizophrenia (t (26) = 6.2, p < .001). On the
faux-pas test, control subjects also performed better than
outpatients (t (27) = 13.5, p < .001), inpatients with positive schizophrenia (t (30) = 11.4, p < .001) and inpatients
with negative schizophrenia (t (26) = 13.5, p < .001). In
the second-order false belief, control subjects had a higher score than outpatients (t (27) = 5.2, p < .005), inpatients with positive schizophrenia (t (31) = 4.5, p < .005)
and inpatients with negative schizophrenia (t (26) = 3.2,
p < .05).
ANCOVAs were computed to assess the effect of group
while controlling for differences in age, level of education and IQ. In these analyses, the scores on each ToM
test were analysed as outcome variables, and age, level
of education and IQ as covariates, and group variable
was analysed as a between subject. These analyses
showed a significant effect of group, after controlling for
the effect of age, IQ and level of education (respectively
in the eyes test: F (3, 43) = 7.7, p < .001; faux-pas test:
F (3, 42) = 37.6, p < .001; and second-order false belief
task: F (3, 43) = 9.4, p < .001). In all these analyses, there
was no significant effect of covariates (age, IQ and level
of education, all p > .05).
Discussion
This study investigated a possible explanation for some
difficulties in social interaction and communication in
patients with schizophrenia. The results revealed the
presence of a specific cognitive impairment in representing and reasoning about mental states. This psychological-reasoning system is composed, to a large extent, of
unconscious processes (modularity theory), and can be
fractionated into two main subsystems, one dedicated, in
most proposals, to reasoning about goals and perception
(actional or teleological understanding) and the other to
belief-desire reasoning 17.
In this study, outpatients and inpatients with negative or
positive schizophrenia performed worse than controls on
three different ToM tasks. ToM impairments were not associated with good prognosis during the chronic phase of
illness, and it presented the same features in the presence
of positive or negative symptoms. These results support
the theoretical model that ToM impairment in schizophrenia is state-independent 4 5.
According to a recent proposal, ToM can be analyzed
into two main components: a perceptual component that
deals mainly with decoding social information from facial expressions and other social signals, and an inferential component, that is responsible for mental state attribution in social scenarios 18. In all three groups of patients, cognitive impairments in social perception (eyes
test) and inferential reasoning (Sullivan’s stories and faux
pas task) were found. These results suggest the presence
of impairment of ToM in patients with schizophrenia that
involves their social skills and negatively influences their
quality of life.
Interestingly, the lower ToM performance of the three
groups of patients could not be explained by differences
in IQ in almost any case. We have no strong interpretation
to explain why the effect of group was no longer significant after controlling for age, IQ and level of education
when comparing controls with inpatients with negative
schizophrenia in the eyes test. Tentatively, symptomatology of patients may change the relationships between
IQ and ToM performance. In addition, we did not find a
correlation between ToM performance and demographical or clinical characteristics in all patient groups. Taken
together, these results provide evidence that ToM is not
linked to specific clinical features or general intelligence.
Shamay-Tsoory et al. 19, using a task with verbal and visual eyes cues, assessed the ‘affective’ and ‘cognitive’ ToM
components (first and second order) in patients with schizophrenia, in patients with lesions localized in the ventro249
A. Geraci et al.
medial or dorsolateral prefrontal cortex, in patients with
non-frontal lesions and healthy control subjects. Patients
with schizophrenia and those with lesions in the ventromedial prefrontal cortex were impaired in affective but not
in cognitive components. They concluded that the pattern
of ToM deficits in schizophrenia resembled those seen in
patients with lesions in the ventromedial prefrontal cortex, supporting the notion of a disturbance of the frontallimbic circuits in patients with schizophrenia. Our data
extend that study by revealing in patients cognitive ToM
impairment in patients with schizophrenia, suggesting disturbances in other neural circuits, such as the temporoparietal junction for false beliefs attribution 20 or the medial
prefrontal cortex for inferential reasoning 21.
The small number of patients could represent a limitation
to this study. However, the results provide several recommendations for future studies. One important issue is to
further test the role of ToM impairment in activity of daily
life in patients with schizophrenia.
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